Boats of the Royal Air Force Marine Branch 1918 - 1986

68ft British Power Boat Company High Speed Launch

Early in 1942, the RAF Marine Craft Policy Committee accepted both Thornycroft and Vospers designs for new HSLs. Whilst the
aforementioned concentrated on their tried and tested hull designs, George Selman at BPBC was able to adopt a more expansive
approach. He was able to concieve an original design which was close to the RAF ideal. The result was the 68ft BPB HSL,
also known as the BPB Type 3 HSL, but nicknamed the "Hants & Dorset". The new HSL was a big and beamy craft in comparison with
all other HSLs, and the interior was palatial after the confined spaces of the other types. The amount of space was further
enhanced by the designer's concept of placing a full hieght deckhouse above the main deck instead of the customary half-height,
recessed deckhouse. Apart from the engine room, which was seperated from the forward sections by the tank space, all working
and accommodation areas of the craft were interconnected, hence the crew were able to move from any part of the deckhouse, via
hatch and ladder to any part of the lower deck without venturing outside.

The hull design was advanced for its day, the chines were lifted at the forward end to create a deep vee forefoot and a soft
wave entry, twisting to an almostflat planning section aft. Although the 68ft HSLs did pound, they were more comfortable
than the BPB 63ft HSLs. They were also slower than the 63ft craft, but could hold a good speed in rough sea.

HSL 2552, the first of the type, arrived at Calshot in October 1942 and after gaining the confidence of RAF crews many more
were ordered and built. A total of 90 of the type were eventually built at Hythe and Poolebetween 1942 and 1946.
Construction gained great pace in 1943 when 69 craft of the type were completed. The last two craft were completed in 1946,
however in 1944 a reassessment of requirements led to cancellation of an order for a further 32 craft originally allocated
numbers 2747 - 2778.

The 68ft HSL was very successful, with many serving into the 1950's, the only one type of 10 wartime HSLs to be retained by
the RAF in the big sell-off after VJ day. With the war over, the role of the craft was changed to that of Rescue and Target
Towing and several craft were given limited or full conversions to Rescue & Target Towing Launches - RTTL Mk.1 configuration.
Limited conversions involved removing the guns and and glass domes, the tubs being retained, whereas in the full conversion
the gun tubs and all associated fittings were removed. In both conversions a small target towing winch and cuddy were fitted
aft. Four former HSLs were also converted to Remote Controlled Target Launches (RCTL), these later being converted to RTTLs.